Material Pollution

Material pollution relates to pollutants in the air, earth and water stemming from the material itself and from its constituents when being processed, used and during decay. The picture is extremely complex, considering that about 80 000 chemicals are in use in the building industry, and that the number of health-damaging chemicals has quadrupled since 1971. Long-term and not easily reversible damage to groundwater systems and local biotopes also occurs during extraction and mining. Some mines dating back to antiquity still cause serious health and pollution consequences today (Grattan et al., 2003).

Material pollution from construction consists of emissions, dust and radiation from materials that are exposed to chemical or physical activity such as warmth, pressure or damage. Within the completed building these activities are relatively small, yet there is evidence of a number of materials emitting gases or dust which can lead to health problems for the inhabitants or users; primarily allergies, skin and mucous membrane irritations. The electrostatic properties of different materials also play a role in the internal climate of a building. Surfaces that are heavily negatively charged can create an electrostatic charge and attract dust. Electrical conductors such as metals can increase existing magnetic fields. Building materials can also contain radioactive constituents such as radon gas that can be emitted to the indoor air.

Waste is part of the pollution picture though, as waste materials move beyond the scope of everyday activity, it tends to be overlooked. The percentage by weight of environmentally hazardous materials in demolition waste is relatively small, but is still a large quantity and has a considerable negative effect on the environment. Whilst some materials can be burned in an ordinary incinerator, others need incinerators with highly efficient flue gas purifiers. Few incinerators can do this efficiently - many still emit damaging compounds such as SO2, hydrogen chloride (HCl), heavy metals and dioxins. Depending on the environmental risk, disposal sites must ensure that there is no seepage of the waste into the water system. The most dangerous materials are those containing heavy metals and other poisons, and also plastics that are slow to decompose and cause problems because of their sheer volume.

There is an evident correlation between the natural occurrence of a material and its potential to damage the environment (Table 2.3). If the amount of a substance in an environment (in air, earth, water or organisms) is increased, this increases the risk of negative effects.

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